diff --git a/secop/datatypes.py b/secop/datatypes.py
index 883a9d7..e7d1a4d 100644
--- a/secop/datatypes.py
+++ b/secop/datatypes.py
@@ -52,7 +52,10 @@ class FloatRange(DataType):
         self.max = None if max is None else float(max)
         # note: as we may compare to Inf all comparisons would be false
         if (self.min or float('-inf')) <= (self.max or float('+inf')):
-            self.as_json = ['double', min, max]
+            if min == None and max == None:
+                self.as_json = ['double']
+            else:
+                self.as_json = ['double', min, max]
         else:
             raise ValueError('Max must be larger then min!')
 
@@ -91,7 +94,10 @@ class IntRange(DataType):
         self.max = int(max) if max is not None else max
         if self.min is not None and self.max is not None and self.min > self.max:
             raise ValueError('Max must be larger then min!')
-        self.as_json = ['int', self.min, self.max]
+        if self.min == None and self.max == None:
+            self.as_json = ['int']
+        else:
+            self.as_json = ['int', self.min, self.max]
 
     def validate(self, value):
         try:
diff --git a/test/test_datatypes.py b/test/test_datatypes.py
index a0bcc59..c5f882b 100644
--- a/test/test_datatypes.py
+++ b/test/test_datatypes.py
@@ -59,6 +59,9 @@ def test_FloatRange():
     with pytest.raises(ValueError):
         FloatRange('x','Y')
 
+    dt = FloatRange()
+    assert dt.as_json == ['double']
+
 def test_IntRange():
     dt = IntRange(-3, 3)
     assert dt.as_json == ['int', -3, 3]
@@ -76,6 +79,8 @@ def test_IntRange():
     with pytest.raises(ValueError):
         IntRange('xc','Yx')
 
+    dt = IntRange()
+    assert dt.as_json == ['int']
 
 def test_EnumType():
     # test constructor catching illegal arguments